LIBRARY OF CONGRESS. 

Gfcijt Cajnirigljt Ifo. 

Shelf. S-SLl. ■ 



UNITED STATES OF AMERICA. 



\ 



SHARPSTEEN'S 



LESSONS IN 



ELECTRICITY 



FOR 



BEGINNERS. 



PUBLISHED BY 

A. A. SHARPSTEEN, 

B1NGHAMTON, N. Y., 
1895- 







Entered according to Act of Congress, in the year, 1895, by 
A. A. SHABPSTEEN, 

In the office of the Librarian of Congress, at Washington. 



Press of Binghamton Republican. 



PREFACE. 



The following pages have been prepared for per- 
sons with a limited education who are desirous of get- 
ting a more thorough knowledge of the science of elec- 
tricity as it pertains to electric lighting and power 
transmission, 

An effort has been made to prepare the work in 

such a way that all the subjects treated can be very 

readily understood by almost any person who has a 

mind to try to understand them. 

Author. 



CHAPTER I. 



INTRODUCTORY 



i . — The average stationary steam engineer thinks 
that he has got his hands full to keep his boilers 
clean and tight, and his engine or engines running 
smoothly, when all at once he has an electric-light 
plant saddled upon him. The old trouble with 
boilers and engines are of small import now, when 
compared with the new perplexities. All is new 
and mysterious. Fuses, switches, branch blocks, 
amperes, volts, electro-motive force, current, and 
many other terms are showered down upon him in 
torrents. 

2. — Well, the only thing to do is to set about it 
and learn something of the new system of lighting. 
In connection with the wiring the fuses are possibly 
the first to give trouble, and it is very easy to get 
a wrong impression in relation to them. 

3. — Great care should be exercised in connection 
with the fuses. "Why," the average man will say, 
"that part seems simple." All things are simple 
to the simple minded, but the doom of every struc- 
ture lighted with incandescent electric light de- 
pends upon the fuses. Perfectly safe if wired well 
and fuses are right. 

4. — You will often hear persons that have to do 



6 SHARPSTEEN S LESSONS 

with electric lights say: "Well, that fuse won't go 
out again. I have put one in large enough to stay." 
If you should ask what was put in you might be 
informed that a piece of bare No. 10 B. & S. gauge 
copper wire was placed where possibly a 5 ampere 
fuse should be. 

5. — The first thing that suggests itself to a person 
is: "What might be the result?" Well, one thing 
that might happen is, a person conversant with 
electrical work might discover the state of things 
and report the same to the inspector of the board 
of fire underwriters, the inspector might go to the 
employer and so represent things that the engineer 
might possibly lose his job. Fire underwriters are 
very exacting in relation to fuses. 

6. — Oftentimes the supports for the wire become 
broken or the wire pulled from them : in such an 
event if the wire gets against the wood- work, and 
the insulation impaired, a current may pass from 
wire to wire through the wood sufficient to ignite 
it. These currents are sometimes called sneak cur- 
rents If the fuse was just large enough to carry 
the load, the extra current ought to open the circuit. 

7. — Where wires are concealed under floors and 
in partitions they sometimes come very close to 
combustibles, and if a fuse is large, controlling a 
14 wire B. & S. gauge running to some outlet, in 
case the bare wires of opposite polarity come to- 
gether, if the source of supply is of any size, ancl 
the loop long enough to make the proper flow of 



IN ELECTRICITY 7 

current, the 14 wire in the loop may get red hot, 
ignite the insulation, and set the building on fire. 
Some people tell about putting wires inside of con- 
duit and then they surely are safe. It matters not 
if the conduit has a heavy iron covering, a wire can 
be heated red hot, and how long before insulation 
and iron will both be hot enough to set fire to 
wood-work ? 



CHAPTER II. 

UNITS. 

8. — We have progressed as far as we can along 
this line without getting some little knowledge of 
what this pressure and current is that is playing 
such a peculiar part in these wires and fuses. Pos- 
sibly there are the words amperes and volts on the 
machine, and i 10 volts may be marked on every 
lamp, what does it mean"" Did it ever occur to you 
that you were establishing standards or units in 
minds by which to measure things about 
you ? 

9. — The people of all grades of civilization have 
units of measurement, but the higher the civiliza- 
tion the more ado there is about what the units are 
based upon, and the more convenient the arrange- 
ment for their use. You have the whole day of 24 
hours divided, and we will say here for convenience 
that your unit of measurement or your " stick*' by 
which you measure the day is the hour, and for 
many uses the hour is large, and then you di- 

the hour into sixty parts and call these parts 
minute^. 

10. — You don't have to take the dial off a clock 
in the morning and. lay out your work so as to get 



IN ELECTRICITY. 9 

back home at noon, but you have the dial fixed in 
your mind, and by occasionally looking- at a clock 
or watch you get around at the proper time, and 
have got done about what you planned in the morn- 
ing. With a little study and thought the electri- 
cal units will become just as familiar to you as the 
divisions of time. After you once get a start in 
the right direction you will keep adding to your 
knowledge and use of the electrical units when you 
least expect to. 

11. — There is a something that pushes the cur- 
rent of electricity along. The unit or measuring 
stick by which this pressure is measured is called a 
volt. There is something that tends to hold the 
current back, and the unit or measuring stick by 
which this resistance is measured is called the ohm. 
When a circuit is closed and the pressure is applied 
there is a something on the move in the wire ; this 
something passing through the wire is commonly 
called a current of electricity ; this current of elec- 
tricity may be large or small, and the unit or stick 
by which it is measured is called an ampere Volt, 
Ohm and Ampere were the names of three cele- 
brated men : no other significance is attached to 
their derivation. 



CHAPTER III 

VOLT. 

_ — The battery that is much used for telegraph 
work and which almost every person has seen, has 
a pressure slightly more than one volt; it is called 

- me the Daniel Battery, by others the Blue- 
Stone Batter}-, from the blue sulphate of copper 
that helps to make up its solution. This battery 
has a pressure of about one volt, and it takes very 
nearly i 10 of them to get a pressure sufficient to 
light a i i o- volt incandescent lamp. Don't under- 
stand from this that 1 10 of these cells would light 
any i 10-volt incandescent lamp that you might 
have, as there are other things besides the voltage 
to consider which we will speak of later. 

— On a machine which is built to run i io-volt 
lamps it matters not if there be one lamp on the 
machine or ioo if the mains are large enough to 
carry the current without any loss ; the pressure is 
the same for the ioo as for the one ; this is shown 
by the voltmeter on the switchboard. It is under- 
stood that the machine is large enough to carry the 
lamps. The same thing might be said of a whole 
city: the pressure for one or 5.000 lamps would be 
the same if thev were carried bv a direct system, 



IN ELECTRICITY. I I 

or came direct from the machines as in the average 
factory, but for long" mains or circuits and only i 10- 
volts pressure the wires or mains would have to be 
very large, which prohibits the use of such a sys- 
tem for city lighting. 

14. — -The street railroad companies use a press- 
ure of 500 volts for their roads. This pressure it 
is claimed will not kill a person, but is very pain- 
ful if the conditions are right, and a person is sub- 
jected to the pressure. 

15. — If the railroad people could use a higher 
voltage they could use much smaller mains, but 
people, especially the motormen, are so liable to get 
the full pressure that the companies have to be con- 
tent with the low pressure. Most of the companies 
now use for incandescent work at least a thousand- 
volts preSvSure ; this pressure is made much lower 
by what is called transformers, before it enters 
buildings for lighting. 

16. — A ten-light arc machine has a pressure of 
about 500 volts when working with all the lamps 
on. A fifty-light machine has a pressure of about 
2,300 volts. Some arc machines have a pressure or 
voltage sufficiently high to burn 100 arc lamps at 
onetime. All arc currents mentioned are consid- 
ered as 10 ampere. Such a machine would have a 
voltage of about 4,600 if the lamps were 2,000-candle 
power. 

17. — As high as 1 1,000 and 25,000 volts we hear 
talked about now for power transmission plants. 



12 SHARPSTEEN S LESSONS 

One arc lamp takes about 45 volts; so a ma- 
chine running" one arc lamp has a pressure of only 
45 volts, for two lamps 90, &c. In speaking of 
pressure in relation to a machine running incan- 
descent lamps, we said that the pressure was the 
same for one or 100 lamps if the mains were large 
enough. 

18. — With the pressure or voltage on a regular 
arc machine the reverse holds true. For every 
lamp that is added, the pressure has -get to be raised 
if the current is kept up to the proper number of 
amperes. One volt pressure would force current 
enough through the coils of the average bell to 
make its magnets pull quite hard. 



CHAPTER IV. 

OHM. 

19.— After the dynamo has run for some time, yon 
can feel some warmth, if you place your hand on 
the field coils . This warmth usually comes from 
the current of electricity passing through the wire 
wound on the fields of the machine, and indicates 
that there is a resistance there of some kind which 
transforms or turns this passing current into heat . 
When a thunder-storm is on, this problem of resist- 
ance and heat is very nicely illustrated. 

20. — The enormous voltage that is made up in 
the clouds pushes the electricity through the atmos- 
phere, and the resistance of the atmosphere is so 
high that the electricity not only makes the atmos- 
phere warm but white hot, and we call the white 
places that we see lightning. The incandescent 
lamp has a resistance that will permit current 
enough to pass to make the filament of the 
proper heat to emit light. As mentioned above, 
the word that is used in speaking of this resistance 
is called the ohm. 1,000 feet of No. 10 B. & S. 
Gauge copper wire, has a resistance slightly more 
than one ohm. 

21. — 1,000 feet of No. 20 B. & S. Gauge copper 



14 SHARPSTEEN 5 LESS 

wire has about loi ohms resistance. 1,000 ft. 
of Xo. 30 B. & S. Gauge copper wire has a resis- 
tance of about 107^ ohms. 1,000 ft. of No. 1 
B. & S. Gauge wire has a resistance of about i| 
ohms. A 1 10- volt, 16-candle-power lamp has a 
resistance of about 180 ohms. 

22. — Xo two metals or substances of the same 
length and cross- sections have the same resistance. 
Of the metals, silver puts the least resistance in 
the path of a current of electricity ; copper comes 
next ; soft iron has about seven times as high re- 
sistance as copper. 

23. — Sometimes people form the idea that a 
current of electricity cannot pass through rubber 
and certain other materials that are called non- 
conductors. This is a mistake ; all metals and 
substances will permit of a current of electricity 
passing through them, but their resistance is sc 
very high that the current of electricity that passes 
is so small that in practice it is often considered as 
no current at all. 

24.- — In speaking of these very high resistances, 
the word meg-ohm is used, which means a million 
ohms. It is a common thing to hear persons speak 
of 2\ or 50 or even 500 meg-ohms when they are 
talking of insulation. 



CHAPTER V. 

AMPERE. 

25. — There are currents of electricity infinitely 
small and others enormously large ever about us 
when we are on the streets of a city, and the way 
they are usually thought of by the practical electri- 
cian, the scientist possibly as well, is in amperes 
or fractions of an ampere. 

When a person that is accustomed to working at 
piping for water conveyance and tinkering the same 
when out of repair, looks at a system of piping that 
is filled with water or steam under pressure, he 
thinks of it in a much different way than he would 
if he knew it was empty. The same is true of a 
person connected with electrical work ; when he 
gets where a number of wires can be seen that are 
conveying currents of electricity, the wires are 
thought of in a much different way than they would 
be if they were known to be " dead," or there was 
no current passing through them. This unit ampere 
is one much used, and we should try and get a pro- 
per conception of it. 

26. — Milampere means a current one- thousandth 
as large as an ampere, and is used in making- 
tests of various kinds, and in medical work. In 
other words, if the ampere was divided into one 



\6 sharpsteen's lessons 

thousand parts, one of the parts would be a mil- 
ampere. 

27. — If a warehouse or isolated plant be properly 
wired, a person may wateh the volt meter or in- 
strument that shows what pressure is being carried, 
and it stands about the same regardless of load. 
The pointer of the ammeter or instrument that 
measures the amperes swings around and indicates 
more amperes as the load gets on. 

28. — Two lamps run from a 1 10- volt machine will 
make a difference of about one ampere. Thus in- 
stead of the voltage or pressure increasing the am- 
peres increase as the lamps or motors go on. 

29. — It was mentioned that the voltage increased 
as the arc lamps were put on a regular arc-light 
machine, and if an ammeter should be in a circuit 
of an arc-light machine which was regulated closely, 
one would notice that the ammeter needle would 
point to one place the whole time, regardless of the 
number of lamps on the machine. 

30 — We are then to understand that the amperes 
or amperage increases as the load increases on an 
incandescent machine, and the voltage remains 
nearly the same; hence an incandescent machine 
is called a constant voltage machine. 

31. — -That the volts pressure increases as the load 
increases on an arc machine, and that the current 
or amperes remain the same, hence an arc-light 
machine is called a constant amperage or constant- 
current machine. 



CHAPTER VI. 

WATT. 

32. — The watt is the rate of doing work or the 
unit of power similar to the unit horse-power used 
in mechanics. There are 746 watts in one horse- 
power. 

How often we hear persons call incandescent 
lamps, 3 watt lamps, 3^ watt lamps, etc., and in 
selling electric power and current for electric lights 
we hear watt hours spoken of. 

33. — It is quite a common thing now to hear dy- 
namos rated by kilowatts. The number of kilo- 
watts determines the size of the machine. Kilo- 
watt means a thousand watts, hence a five-kilowatt 
machine means a five-thousand- watt machine. 

34. — If we know the number of amperes of current 
and volts pressure of a machine, we multiply one 
by the other and divide the product by one thous- 
and, and the result that we may get will be the 
kilowatts of the machine. As an example, if the 
machine has wire on its armature large enough to 
carry 100 amperes of current, and develops a pres- 
sure of 1 10 volts with full load, we multiply 100 
amperes by 1 1 o volts and get 11,000 watts. The 
machine then would be a 1 1,000- watt machine, and 



I 8 sharpsteen's lessons 

if we divide the 1 1,000 watts by 1,000 we get i i, 
which means that we have an 1 1 -kilowatt machine. 
35. — If we should want to find what the output in 
horse-power" of any dynamo was of which we might 
know the volts, pressure and amperes, all that is 
necessary to do is to get the watts and divide the 
same by 746. An example : 

A 500 volt and 200 ampere machine. 
500X200=100, 000--746=134 H. P. 

There is something more to be considered in re- 
lation to this unit watt before we have a proper 
conception of the same. 

36. — We may get into a boiler house of an elec- 
tric-light station and look at a number of tons of coal 
and say that there is energy enough stored up there 
to do a certain number of watts of work, or in other 
words so many horse-power of work, and then we 
commence to compute or figure on the problem. 
We find the dynamo is carrying 35 amperes of cur- 
rent at 1,040 volts pressure. 35 amperes x 1,040= 
364, 000 watts or about 49 H . P. We have 49 H . P. and 
a certain pile of coal in the boiler house ; two hours 
later we have 49 H. P. and much less coal in the 
boiler room. 

37. — Thus far in our problem we have demon- 
strated that the coal pile keeps getting smaller, but 
we are still developing 49 horse-power. 

There is one thing passing that we have not 
taken into consideration, and that is time. 49 H. P. 



IN ELECTRICITY. 1 9 

for one hour's time takes a certain amount of coal. 
Now we commence to get out of the mist. 

38. — When speaking of doing work or selling 
energy to do work, we must always consider time. 
The water may lie above a mill dam, and down near 
the water wheel there may be great pressure, but 
there won't be any work done or energy consumed 
until the water commences to move through the 
wheel, and if the machinery is belted to the wheel 
and the wheel runs for an hour a certain amount of 
work is done, and a certain amount of water under 
pressure has passed through the wheel and is no more 
above the dam. 

39. — We hear lamp hours spoken of, meaning 
possibly one 16-candle- power lamp burning for a 
certain number of hours, but a person can hardly 
find two 16-candle-power lamps taking exactly the 
same amount of current ; so a 16-candle-power lamp 
hour is a poor measuring stick or unit to measure by. 
And then again the pressure may vary. For in- 
stance, a person may be near the station and get 1 1 5 
volts pressure when others are getting but 110, 
hence the former is getting much more energy than 
he is paying for. Where a person buys electrical 
energy by the watt hour and gets the same through 
a good recording watt meter, he pays for the 
energy he gets — that is, the volts pressure and 
amperes current are both taken into consideration. 

40. — Now, understand that in selling electrical 
energy for any purpose by a watt meter, time is 



20 SHARPS TEEN S LESSONS 

always considered with volts pressure and 
amperes current. Also remember that in selling- 
lamps, motors and dynamos, only volts and amperes 
are considered. 

41. — When a three-watt 1 10 volt 16-candle-power 
lamp is spoken of it means a lamp that will take 
three watts of energy to keep it up to rated illu- 
minating power for each candle of light ; hence 
three watts x 16-candle-power would make a pro- 
duct of 48 watts for one 16-candle-power lamp, 
and since the volts pressure that the lamp re- 
quires is 1 10, we divide the 48 watts by 1 10 and 
get Tiir of an ampere. 

Xow, we have found that in order to get watt 
hours we must multiply volts pressure by amperes 
current, and again by hours of time, hence volts 
X amperes x time in hours=watt hours. To get 
watts we have found that we are to multiply volts 
by amperes, and when we have watts and volt- 
age given and want to get the amperes, we are to 
divide the watts by the volts pressure. 

42. — As an example we will consider an 880 watt 
machine having a voltage of 110. To find the 
amperes we divide the 880 watts by 110 volts 
and get eight amperes, and if we have an 880 
watt machine and its amperage is 1.8 or i T V, we 
divide 880 by 1.8 and get 500 volts very nearly. 



CHAPTER VII. 

ohm's law. 

43. — Thus far we have spent our time in getting 
our thoughts in some order so that we can concen- 
trate them. 

Two persons may work side by side with the 
same tendencies and mental abilities. The one 
may be systematic in thought, and day by day grow 
in mental vigor and strength in a way that will be 
surprising, while the other who does not work men- 
tally with some system, will possibly do more hard 
thinking, but never have any practical idea about 
what he has been working and thinking, and never 
move up to a higher plane of thought and action. 

We have gone over the subjects treated in a very 
simple way, but should have acquired some foun- 
dation upon which to build something a little more 
substantial. 

44. — We will next undertake to study out what 
is meant by Ohm's law, and how to use the same to 
help us think' aright about electrical matters. 

45. — The term Ohm's law may sound to us as if 
it might take some profound mind to comprehend 
it, but such is not the case. Of all the simple 
things to understand this is one of the simplest, if 
only we will give it a little thought. 

46. — The question as to what use Ohm's law is 
may arise, and we will say right here that it helps 



22 SHARPSTEEN S LESSONS 

us to comprehend many things, the simplest of 
which are : When we have volts pressure of a ma- 
chine or batteries, and the ohms resistance of our 
copper wire or circuit, we can tell what current is 
going to flow. If we have volts pressure and know 
the amount of amperes current that we want to 
pass through any circuit, we can tell just what size 
wire to put in or just the ohms resistance to put in 
to get the desired result. 

47. — If we know the ohms resistance of any cir- 
cuit and the amperes current that we want to pass 
through said circuit, we can determine the number 
of volts pressure that is necessary to use. 

48. — To try and make the case plain we will con- 
sider that we have got a mill dam 20 feet high, and 
that we can bore holes in it. If we make a one- 
half inch hole, say two feet from the bottom of the 
dam, we will get a certain size jet of water through 
the hole ; if we put in the second hole same size, 
same height, we get two times the water we did 
first. The head or pressure of the water we can 
compare with our pressure in electricity. When 
the dam is perfectly tight the resistance is so high 
that no water can pass through, hence the dam is 
similar to resistance in electrical parlance. If we 
remove some of the resistance by making a hole in 
the dam, water flows; hence we may compare the 
water flowing to the current of electricity passing 
through a wire. 

49. — When we start up our dynamo and discon- 



IN ELECTRICITY. 23 

nect the outgoing circuit if the brushes are down, 
field circuit closed, and we have the proper speed, 
with a shunt machine we get a pressure, but there 
is no current flowing outside the machine, and we 
ask ourselves " Why ? " and the answer is: " The 
machine is surrounded by a dam that keeps the 
current of electricity from flowing. Electricity 
won't pass through the atmosphere or wood about 
the machine, because, like the dam to the water, 
the air and the wood won't let it go through. Now 
if we cut a hole in this dam of air by putting a 
piece of copper through it, we have a path along 
which the current will pass. 

50. — To get back to Ohm's law, which is written 

thus: 

~ ^ n • Volts pressure. 

Current flowing = Qhms re&istallce . 

or, to write the whole thing out : Current flowing 
is equal to the volts pressure divided by ohms re- 
sistance. 

We will suppose that the dynamo just mentioned 
has a pressure of 100 volts, and when the pressure 
is up, we put 100 feet No. 30 B. & S. gauge wire, 
which has a resistance of about 10 ohms, from the 
positive to the negative brush, then we try and 
find from Ohm's law how much current is flowing 
in this hole that we have cut into our dam. 

Volts pressure of the machine 100. 

"Oh ms resistance of wire 10. — = IO amperes current. 

51. — Now if we put another piece of wire 100 
feet No. 30 B. & S. gauge from pole to pole of the 



24 sharpsteen's lessons 

machine we will have, at first thought, many would 
say, "20 ohms," because one piece has a resistance 
of 10 ohms, two pieces would have twice 10 ohms, 
or 20 ohms resistance. This, on reflection, we will 
find is not true, when we put the second piece of 
copper from pole to pole we double the size of the 
copper, we have a cross from brush to brush, 
hence instead of a No. 30 we have about a No. 27 
wire, and instead of 10 ohms we will have about 5 
ohms, hence we have cut the resistance down one- 
half, and our problem becomes : 

Volts pressure 100 
"F ive ohms = 20 amperes. 

It is just the same as cutting an inch hole in our 
mill dam and getting a certain flow of water. Now 
if we put another inch hole beside the first we 
don't raise the resistance or obstruction to the 
water, but we lower it and make twice the size 
opening, hence twice the amount of water flows. 

52. — Possibly we have been in a large crowd of 
people waiting to get through a small gate. If a 
second opening was made by adding another gate, 
twice the number of people would pass ; it would 
be cutting down the obstruction, not making more 

of it. 

i 

53. — The copper put from pole to pole of the 
machine is similar to the gate, one piece will let a 
certain amount of current How, two pieces of the 
same gauge will let double the amount of current 



IN ELECTRICITY. 2 §. 

flow, hence the obstruction or resistance to the cur- 
rent has been lowered. 

54. — Having illustrated Ohm's law so that almost 
any person can get an idea of what it is used for, 
we will become more brief and try and apply it 
somewhat. This is how we usually see it written : 

C = g or we might put it thus : Amperes = t^ s 

C stands for current in amperes. 
E for pressure, or E. M. F., which means elec- 
tro-motive force in volts. 
R for resistance in ohms. 
Then we can transform the formula and put it 

thus: When we have volts and amper^^nd want 

■pi 
to find ohms, ohms or R = ~, and when we have 

C and R and want to find E, we put it thus: 
E-CxR. 

It may make this transformation plainer to illus- 
trate it with figures, thus : 

2 ===== 1, or 3 = «, or 6 = 2 x 3. 

55. — Examples: 

[a] A dynamo with a pressure of 1 10 volts gen- 
erates a current of 100 amperes when its load is 
on. The 1 10 volts is shown by the volt meter on 
the switchboard, and the 100 amperes is shown by 
the ammeter on the switchboard. What is the re- 
sistance of the circuit and lamps when the machine 
is generating the 100 amperes? 



26 sharpsteen's lessons 

d / \u -1 H° volts 1 , 

Hv ( )hm s law ^rx = i^ ohms. 

100 amperes current. 10 

[/?] Instruments on switchboard show a pressure 
of i io volts and l /2 ampere: what is the resistance 
of the lamps and circuit"' 

[c] Instruments on switchboard show a pressure 
of 560 volts and amperage of 500: what is the re- 
sistance of external circuit? 

[d] The resistance of a given circuit is two ohms 
with all lamps turned on, and the voltage is 1 10. 
what is the amperage ? 

[e] The resistance of a given circuit is five ohms 
with lamps on, and the amperage or current is 100; 
what is the voltage? 

[/] The amperage of a given circuit is 10 with 
load on, and the voltage 5,000: what is the resist- 
ance ? 

\_g] An electric bell with a resistance of three 
ohms is put in circuit with a grove cell of battery 
that has an internal resistance of tV of an ohm 
and a voltage of 1 h ; what current will flow 
through bell and battery when the circuit is closed, 
assuming that the wire connecting bell and bat- 
tery is so short that its resistance is nil? 

\Ji\ No. 10 B. & S. gauge wire has a resistance 
of about one ohm to the 1,000 feet. If we put 
1,000 feet of this wire in circuit with a i 10 volt 
machine of large capacity, what current will we 
get' 



IN ELECTRICITY 27 

[z] Assume we have 70 pounds No. 23 copper 
wire B. & S. gauge that we intend putting on the 
fields of a 5 00- volt moter; what amount of current 
in amperes will pass through the wire, the resist- 
ance of the wire being about 950 ohms? 



CHAPTER VIII. 

SERIES CIRCUITS. 

5 — How often we hear persons speak about 
electric lights or motors being put either in series 
or multiple. The multiple circuit is treated under 
Xo. £6. Almost all the arc-light circuits of the 
world are what are called series circuits. 




57. — By tracing the wire around in the cut it will 
be seen that the whole current passes through all 
the lamps, hence we might define a series circuit 
as one in which the whole current passes through 
every foot of wire, and every piece of apparatus 
put in circuit. 

All have to let the same current pass through 
them, with these exceptions, in case of leakage as 
from A to H by a wire across the circuits or from 



IN ELECTRICITY. 29 

faulty construction some of the current may pass 
across and not go through the lamps beyond the 
trouble. 

Another exception is in the lamp where a small 
portion of the current usually passes around the 
carbons through what are called the shunts or fine 
wire magnets that are used in the regulation of the 
arc in the lamp . Practically speaking, the whole 
current in the arc lamp passes through the carbons. 

58. — All the current that may pass through the 
fine wire magnets in the arc lamp is a dead loss of 
energy, as far as light is concerned. This current 
is usually very small. One good feature of the 
series system is that the single wire can be run 
along one street, and back some other street, or a 
circuit can run hither and yon through a whole 
town, feeding lamps at any point on said circuit. 

59. — One of the great redeeming features of the 
series system is that a large amount of energy can 
be transmitted over a large area with a small 
amount of copper. 

60. — As mentioned farther back, with a series 
circuit the pressure increases as the lamps or mo- 
tors are put in the circuit. It usually takes about 
45 volts on a 10 ampere circuit to produce a nomi- 
nal 2,000-candle-powerlight. If we switch in lamp 
No. 1 in the cut, and consider that all the rest are 
switched off, if the wire is No. 6, B. & S. gauge 
and very short, there will be a difference of about 
45 volts at the binding posts of the machine, 



SHARPSTEEN S LESS< NS 

61. — The pressure at the brushes, if it be a series 
machine, will be much greater since the 10 am- 
peres of current has got to be forced through a 
great length of wire on the held magnets. There 
are series iynamos as well as series circuits, but 
the -eries circuits we are considering new. 

When we switch in lamp No. 2 :here will be a 
difference of 90 volts at the machine. By adding 
N 3 the pressure will come up to 135 volts, and 
so on until the whole number is on. but we have 
learned that the current remains the same, hence 
this is a constant-current circuit. 



CHAPTER IX. 

LOSS OF ENERGY IN CONDUCTORS. 

62. — This brings us up to another important sub- 
ject that we must understand in our reasonings 
about electrical matter, and since we have ac- 
quired some knowledge oi the electrical units, we 
can get a very clear idea of it. 

63. — We have found that any conductor will offer 
more or less resistance to the current of electricity 
that may pass through it. This resistance turns a 
portion of the current passing into heat, and we 
usually consider that such amounts of energy as are 
turned into heat are wasted, hence we call it a loss 
of energy. 

64. — This loss of energy is directly proportional 
to the square of the amount of current in amperes. 
To make it more plain, if we have two arc circuits 
each live miles long, and Xo. 1 circuit is made up 
of No. 6 copper wire, B. &S. gauge, it will have a 
resistance of about 1 1 ohms. To force a current of 
10 amperes through a resistance of 11 ohms, will 
take, according to ohms law, 10 amperes multiplied 
by 1 1 ohms resistance, equals 1,10 volts. 

65. — We learned farther back that volts multi- 
plied by amperes gave us watts, and watts showed 
us what amount of energy was being consumed at 
any time when current was passing, hence 1 revolts 



32 SHARPSTEEN S LESSONS 

multiplied by 10 amperes gives us i.ioo watts. We 
are to understand then that more than one horse- 
power of energy would be consumed in the wire 
alone, when a current of 10 amperes was passing 
through five miles of No. 6 wire, B. & S. gauge. 

66. — No. 2 circuit we will consider is composed 
of No. 9 copper wire, B. & S. gauge, five miles of 
which will have a resistance of about 22 ohms 
According to ohms law, to put 10 amperes through 
resistance of 22 ohms will take 22 times 10 or 220 
volts, and 220 volts times 10 amperes gives us 2,200 
watts, just double the amount of energy that was 
used up in the No. 6 wire ; hence we have demon- 
strated that the loss of energy in a conductor with 
a certain amount of current flowing is doubled if we 
double the resistance, or as we said in the commence- 
ment of this explanation, that the loss is directly 
proportional to the resistance. 

67. — Examples: 

[a] What is the loss of energy in watts in a cir- 
cuit of 1^2 ohms and 12 amperes of current? 

[6] What is the loss of energy in watts in a tele- 
graph circuit of 10,000 ohms .02 or ih of an am- 
pere current? 

\c\ What is the loss of energy in watts in the 
mains between machine and first lamp, feeding 
400 16-candle-power lamps, ammeter indicating 200 
with load on? The size of the wire is such that 
there is a loss of five volts in the two legs of the 
mains. 



CHAPTER X. 

PRESSURE AND LOSS OF ENERGY. 

68. — We will now demonstrate that increasing 
the pressure in any circuit will not increase the 
amount of energy lost as long as the current and 
resistance remain the same. 

69. — As an example we will take a case where a 
50-arc light machine 10 amperes of current is at 
night-time furnishing the necessary electrical en- 
ergy to burn 50 arc lamps in a town five miles from 
the machine. Understand that there is five miles 
of wire in each leg of the circuit without anv 
lamps, thus : 



5 M fLLS 




5 MILES 

FIG Z 



70. — Early in the evening there are 25 of these 
lamps turned on in the stores, &c, then at the 
terminals of the machine we will have a pressure 
of 45 X 25 = 1,125 volts to force the current through 
the 2 5 lamps -t- 2 1 7 volts to force the current through 



34 SHARPSTEEX S LESSONS 

the 10 miles No. 6 wire +60 volts used in forcing 
the current through the circuit in the town= 1,402 
volts pressure at the machine. What we want to 
find out now is just the amount of energy lost in 
our ten miles of wire between the towns when 
these 25 lamps are on, and we have 1,402 volts at 
the machine. 

Ten miles of No. 6 copper wire, B. & S. gauge, 
has a resistance of 2 1 .7 ohms, and according to ohms 
law, it will take 10 amperes X 2 1.7 ohms to get the 
voltage necessary to force the 10 amperes through 
the 10 miles of wire, wmich will give us 217 volts. 
Now to get the watts of energy lost, we will have 
to multiply 217 volts X 10 amperes, which will give 
us 2, 170 w r atts, or when divided by 746 will give us 
2.9 horse-power lost in this ten miles of wire when 
the electrical energy is passing through it at a volt- 
age of 1,402. 

Later in the evening the street lamps are 
switched in circuit and the pressure at terminals of 
the machine comes up to 1,402 volts + 1, 125, the 
voltage necessary to force the 10 amperes current 
through the additional 25 lamps=2,52 7 volts. 

71. — Now the pressure of the current passing 
through the five miles of wire between the towns 
has almost doubled, but we lose no more energy in 
it than before, for we have the same resistance in 
the wire between the towns, and the same amount 
of current flowing, hence the amount of energy 



IN ELECTRICITY. 35 

lost is the same for the 2527 volts strain as for the 
1402 volts strain. 

72. — Hence we have demonstrated that increas- 
ing the pressure of the current passing through a 
wire does not increase the loss of energy in the 
wire. This makes plain to us why it is that elec- 
trical engineers are ever trying to devise some 
scheme by which they can transmit electrical en- 
ergy at high pressures and still have it safe to han- 
dle and convenient for use. If there was no limit 
to the voltage large amounts of electrical energy 
could be sent for thousands of miles on very small 
copper wires, or even iron wire. 

Year by year the devices are getting better, and 
the voltages raised, hence the problems of power 
transmissions are getting more practical. Here is 
a field for almost any man to work into, as it is a 
large and promising one. 



CHAPTER XL 

INCREASE OF CURRENT AND LOSS OF ENERGY. 

73. — Thus far we have demonstrated that if we 
double the resistance with a certain amount of cur- 
rent flowing we double the amount of energy lost 
in the conductor if the amount of current remains 
the same in both cases. We have also demon- 
strated that increasing the pressure or tension of 
the current passing through the wire does not in- 
crease the loss of energy in said wire as long as the 
resistance and amperes remain the same. 

74. — When the current is increased, the loss of 
energy increases very rapidly, which will now be 
demonstrated. 

75. — By using circuit No. 1, which was five miles 
of No. 6 wire B. & S. gauge, we have a resistance 
of 1 1 ohms, and it was demonstrated that to force 
10 amperes of current through this five miles of 
wire of 1 1 ohms resistance required a pressure of 
1 10 volts, or according to ohms law, when we have 
ohms and amperes to find volts we multiply the 
ohms by the amperes, thus : 1 1 ohms multiplied by 
10 amperes of current gives 110 volts; to get the 
watts, 1 10 volts just found multiplied by 10 am- 
peres of current gives us 1,100 watts. This is for 



IN ELECTRICITY. 37 

10 amperes through five miles No. 6 wire or 11 
ohms. 

j6. — Now we will increase the current to 20 am- 
peres and see what results we get : 20 amperes 
multiplied by 1 1 ohms gives 220 volts. To find 
watts, 220 volts multiplied by 20 amperes gives us 
4,400 watts. 

7 7. — It is plainly demonstrated that when the 
current is increased and the resistance remains the 
same, the loss of energy increases very rapidly. It 
should be observed that the pressure had to be 
doubled as the current was doubled, so that the 
actual loss in watts is four times as much for the 
20 as for the 10 amperes. 

This makes it quite plain why the Electrical En- 
gineer is ever trying to keep down the amperes 
current all that it is possible. 

78. — It is not only a question of loss of power, 
but the trouble that arises from the loss of pressure 
is very great. 



CHAPTER XII 



CARRYING CAPACITY r ORES 



" — Wher :re ?e^:-ie: : :rrrrer::e- :: ~ike 
calculations in determining sizes of wire for car- 
rying any number of incandescent lamps, the safe 
carrying car. - the first thing to think of. On 

rererr:-^ :■: tables he ~ s "-: ±-i tha: sis :-:r. r-eres 
•was considered safe for a No. [4 wire I feS 

ge. He may have 12 or 13 lamps that he wants 
to -wire in some outbuilding say doo feet 

from the mains carrying current for main building 
r : rom the dynamo. Th - : lamps are 
connected np. current turned on, but for 
son the lamps don't seem to burn prop 
are dim. Now there is a terrible thinki 
the lamps are changed, the fuses changed 
to no avail — the lamps will not burn brightly. 

— After :":u:ry :r :Lcse : r>erva:::r: the 
trouble may he found, when the beginner is im- 
pressed with the fact that there is something besides 

thing is comnio: d "drop," or loss of pres- 

sure. We will find by Ohm's law what pressure 

:r.e ':-;.-:- '-.: \ ;-.: :he er ' f the :•:•: fee: ::' v.--. re 

— The resistance of 1,000 feet of No. 14 cop- 



IN' ELECTRICITY 39 

per wire B. & S. gauge is about 2.59 ohms. Mul- 
tiplying 2.59 by 2 because there are two lengths, 
or one out and another back, we get 5.18 ohms. 
Twelve good lamps 16-candle power of 1 10 volts 
will use about ]/ 2 ampere to the lamp, or six am- 
peres for the 12 lamps. 

82. — We now have amperage and resistance, and 
according to Ohm's law if we multiply them to- 
gether we get the volts, hence 5.18 times six am- 
peres gives us a result of 31.08 volts. Thus we 
have found that it will require over 31 volts to 
force six amperes of current through 2,000 feet of 
No. 14 wire, B. & S. gauge. 

83. — The voltage of the dynamo being 1 12 at the 
machine or switchboard, since the pressure is usu- 
ally carried a little high there for the reason that 
there is always some loss in a circuit. 

84. — Well, with 112 volts at switchboard, less 31 
volts that was necessary to force 6 amperes of cur- 
rent through 2,000 feet No. 14 wire, we would 
have 8 1 volts pressure at the lamps. This demon- 
stration makes it plain why the lamps in outbuild- 
ings did not burn properly. 

85. — There are almost as many formulas for com- 
puting sizes of wire as there are hairs in a man's 
head, but they are of very little use. 

86. — A good wiring table for 50 and 1 10 volts is 
convenient for reference when a person is daily 
computing sizes of wire for buildings. ' 

87. — With an isolated plant, where the building 



40 SHARPSTEEN S LESSONS 

is not very large, or the wire is to start from the 
switchboard or very near it, three per cent drop is 
all right with the average load, but when the 
source of the current is far away and there has got 
to be some loss in the mains and transformers, the 
house wiring should not have much drop for good 
work. 

88. — It is a common thing to find a difference of 
ten per cent in the voltage between one lamp on 
and all lamps on in buildings lighted either by cen- 
tral stations or isolated plants. This is a very bad 
state of things, and should always be avoided for 
permanent work . 

89. — If one gets Ohm's law well fixed in his 
mind it is an easy thing, with the use of a proper 
wire table, to determine the wire sizes for any dis- 
tance and any number of lamps. 

90. — A person should always know the drop or 
loss of voltage before he commences to compute 
the sizes of wire for a job. 

91. — Examples: 

A section of a factory is to be wired for 18 lamps ; 
the middle of the room or section is, along the 
paths the wires must take, about 100 feet from the 
switchboard or machine, drop three volts, voltage 
1 10, lamps will take about y 2 ampere each. 

If a wiring table is handy it will be found that 
about No. 12 H. & S. gauge is the size, and No. 12 
has a resistance of 1.5 ohms to the thousand feet ; 200 
feet, or 100 feet each way, would be % of a thousand ; 



IN ELECTRICITY, 4 1 

1.5 divided by 5 equals .3 ohms resistance, multi- 
plied by 9 amperes, the current taken for 18 lamps, 
equals 2.7 volts, or very nearly the three volts. 

92. — Commercial copper has a higher resistance 
than the copper from which these tables were com- 
puted, hence we are on the proper side. Practi- 
cally we might be a little high rather than low if 
an actual test was made with the wire in place, as 
sometimes the copper runs a little small, and in put- 
ting it up more is used than usually one thinks; so 
if a person is contracting to have a certain drop 
and wants to be on the safe side ; the copper must 
be put in a little large . 



CHAPTER XIII. 

MEASURING WIRES. 

93. — Before we commence computing and deter- 
mining wire sizes to any extent, it is essential that 
we should know something ubout Mils. Circular 
Mils, &c. 

94. — The inch and foot are very convenient in 
measuring such things as stone and lumber, but 
when they are used for measuring wire, things 
change materially. The inch is too large for dia- 
meters and cross sections of wires, and too small for 
lengths, hence we might hear a person say: — "We 
used on the fields of that machine wire about 1 1 
mils diameter and five miles long.'* 

95. — The results that have come about are these: 
For measuring diameters and cross sections of 
wires the inch has been discarded and the word 
mil used, which is the one-thousandth part of an 
inch. 

96. — To a person who has never used a micro- 
meter caliper it seems like folly to speak of a thous- 
andth part of an inch. When we look at a steel 
scale divided into 64ths we make the remark that 
it is hard to read and determine sizes even to64ths. 
This is true : but it is much easier to read thous- 
andths of an inch with the caliper than it is 64ths 



IN ELECTRICITY.: .43 

with the scale. In working mica and computing 
sizes of wire, the mil means dimensions that can 
be understood just as plainly as the lumberman 
understands the inch. 

97. — If we get the proper understanding of the 
way in which the dimensions of wires are to be 
computed, it will save us many a muddled thought. 
The whole thing is very simple, but there are but 
few in the electrical business that seem to under- 
stand it. 

98. — Diameter is the distance across a circle ; 




radius is the distance from the circumference to 
the center, or just one-half the diameter; thus A B 
is the diameter of the circle in figure 3, and C D 
the radius. 

99.— We must understand that diameter and ra- 
dius are straight lines. When sectional area is 
spoken of it means the whole surface of the sec- 
tion, or, in other words, if we cut the end of a bar 
of metal square off so as to make the cut surface 
at a right angle to the side of the bar, this cut 



44 



SHARPSTEEX S LESSON: 



surface will be the sectional area of said bar, be it 
a square, flat, or round bar. 

100. — If we have a piece of two-inch round iron 
and we are asked the diameter, and if we are not 
sure what it is we can put a rule across the end and 
soon determine, and half the diameter is the 
radius. If some person asks us what the sectional 
area is in square inches of the same piece of iron, 
then the question is not so easily answered. 



/ IN 

F/6 4 



ioi.-We must get in the habit of thinking of 
wires by their sectional areas, or. in other words, 
by their actual size and weight. Round bars in- 
crease in weight and sectional area just in propor- 
tion to the square of their respective diameters. 
To square a number means to multiply it by itself, 
thus the square of the number 2 is 2x2, or 4; of 
10 is 10x10. or 100; of 2y 2 is 2^x2^, or 6%. A 
square inch of iron means a piece of iron an inch 
square, or an inch on every side, as in Fig. 4. A 
piece of round iron with a sectional area equal to 
one square inch has a surface across the end more 
than one inch in diameter. 



IN ELECTRICITY. 45 

102. — We will consider that we have a number 
of bars of round iron one foot long, of which we 
want to get the comparative weights. A, the 
smallest one, we will say has a diameter that will 
give an inch sectional area; B, another bar, is two 
inches in diameter, and to get the weight and sec- 
tional area compared to the first, we square its di- 
ameter and have 2x2, or 4. Hence we have 
found that we have four times the sectional area 
and four times the weight as with the inch bar. 

[C]. With a bar four inches in diameter we would 
have the square of 4, or 4x4, which is 16, or six- 
teen times as much iron as in the first, or inch bar. 

103. — It is very fortunate that the weights and 
sectional areas of circular bodies are proportional 
to the squares of their respective diameters, espe- 
cially so for persons engaged in the electrical busi- 
ness. 

104. — By looking at the wire table we find that 
opposite the gauge number in column one are 
numbers giving the diameters of all the different 
gauges or sizes, in mils, or in thousandths of an 
inch. Since the sectional area of a wire is propor- 
tional to the square of its diameter, we can get the 
sectional area, or actual size, of the wire in circular 
mils by multiplying the number of mils by itself. 

105. — No. 30 wire we find has a diameter of 10 
mils. To get the sectional area we square this 10 
mils thus: 10x10 and get 100. Now this means 
that a No. 30 wire B. & S. gauge is equivalent in 



46 shakpsteen's lessons 

size to ioo wires one mil in diameter, or, in other 
words, has a sectional area of ioo circular mils. 
A No. 10 wire B. & S. gauge has a sectional area 
of 1038 1 circular mils, or is equivalent in size to 
1 03 8 1 wires one mil in diameter. 



CHAPTER XIV. 



MULTIPLE CIRCUITS. 



106. — Under No. 56 we spoke of series and mul- 
tiple circuits. The series circuit was there dis- 
cussed, but, for good reasons, the multiple circuit 
was left until now. In the early days of electric 
lighting the linemen and others connected with the 
electrical business soon got the idea of putting up 
arc lamps, as only one size wire was used through- 
out, as there was always one quantity of current, 
either ten or twenty amperes. The 10 ampere 
people used No.. 6 wire, B. & S. gauge, and the 20 
ampere people No. 4 wire, B. & S. gauge. When 
a station was started, as a rule, they held to either 
the 10 or the 20 ampere current, and even if both 
kinds were used the linemen knew the two kinds 
of circuits and knew the sizes of wire to use. 

107. — When an incandescent machine was put in 
and the multiple circuit was to be run, then things 
changed, and the poor linemen were troubled. The 
shrew r dest of them would grasp at every straw of in- 
formation; but oh, what a muddle and mystery 
when they heard of drop, ohms, sectional area, and 
found that the size of wire could only be deter- 
mined by computations for every lot of lamps wired. 



SHARPSTEEN 5 1 5S 

108. — Many men learned the business ••parrot 
fashion" by working with skilled men, and if they 
got their training by working on 1 10 volt circuits, 
possibly later they would get into the employ of 
people about to use 52 volt lamps, and the result 
would be that all the wires used would be too small. 

109. — What we mean by '-parrot fashion" is this: 
a helper who had no theoretical training, in work- 
ing with a skilled wireman would get a knowledge 
of about the size wire that was necessary for cer- 
tain numbers of lamps with the voltage that was 
to be used where they were working. The helper 
would conclude that these same sizes of wire would 
do for any lamps of same candle power. 

1 10. — These notions of linemen have been the 
cause of the loss of many a customer for the electric- 
light people, and the reason why a great many 
incandescent plants have not earned dividend 

1 1 1. — When a series circuit is spoken of we think 
of one long stretch of small wire, never varying in 
size, and carrying one quantity of current. 

112. — At first thought this seems like a very 
nice way of transmitting current, and the circuits 
seem so simple and cheap : but when the circuit is 
departed from and the generators and loads are 
considered, the problem becomes very complex. 

113. — The multiple circuit is a little more dim- 
cult to understand to commence with, but as a per- 
son learns of it and uses it, the whole thing be- 
comes attractive. 



IN ELECTRICITY. 49 

114. — The ease and simplicity with which the 
generators can be made to work on these circuits 
with varying loads is remarkable. The way in 
which lamps and motors can be wired on these cir- 
cuits without interfering with other lamps and mo- 
tors on the same circuit is also remarkable. 

1 15. — With a series circuit if the wire comes out 
of the binding post of a lamp or motor the whole 
circuit is shut down, and all the customers have to 
wait until the trouble is looked up. 

116. — With the multiple circuit any customer 
can pull down all the wiring in his place, and it 
would have no effect upon others on the same cir- 
cuit. 



CHAPTER XV. 

TWO-WIRE SYSTEM . 




00 



FIG. 5. 

117. — By way of illustration we will consider 
that in Fig. 5 A is the armature of a dynamo, C is 
the commutator of the same machine, and that at- 
tached to B and B, the brushes, are two large 
wires, one, F, extending downward, and the other, 
G, extending up to the ammeter M, and then down 
to H. Now if we were going to put our lamps in 
series they would be arranged like Fig. 6 ; after 
leaving the ammeter the lamps would be strung 
along in a string as represented, same as the arc- 
lamps as illustrated under No. 56, but we are not 



IX ELECTRICITY. 



51 



going to put them in series ; we are going to 
put them in multiple, as that is the best. 




e- 



+^ 



-e- 



■e- 



F lb 6 



118. — We commenced at the large wire, H, and 
run out to lamp No. 1 and then back to the wire F, 
and since we have 1 14 volts at the machine and the 
pressure is on, and the lamps connected up, if we 
turn on the current at the key in the socket the 
lamp burns. The wire, we will consider, is 1 15 178 
circular mils in area and 1,000 feet long from wire 
H back to wire F, Fig. 5, just large enough to 
carry }4 ampere with four volts loss ; hence we have 
1 10 volts at the terminals of the lamps. 

1 19. — We want to use another lamp in the same 
room. Well, what are we to do? Xo. 1 circuit is 
just large enough to carry lamp No. 1. We will 
go back to the large wire and run circuit No. 2, and 
put in lamp Xo. 2, same length of wire and 
same size. We wire up lamps 3, 4, 5. 6 and 7 
all in the same way, and when they are all turned 
on we have seven lamps of 110 volts at their 



52 5HARPSTEEN S LESSONS 

terminals, hence we have a pretty nice light. 
Some one will say. "Why, it is not eustomarv 
to run a circuit for each and everv lamp, is it?'' 
We say -Yes." on a multiple system a circuit is 
run for each and everything that is wired in : each 
circuit must go right back to the dynamo. 

1 20. — --But.*' a person will say. • -that is nonsense, 
we know better." It is true just the same, there 
must be a metal circuit of some kind for each piece 
of apparatus or lamp tha; goes n a multiple circuit. 
It is not necessary that all these circuits should be 
a wire bv themselves like we illustrated in Fig 5 . 
Thev can all be combined in one bundle of wire 
and be run like the circuit in Fig. -. 



« *^ 




~ -r e $ $ e $ 



121. — Here we will consider that we have com- 
bined the seven wires of the circuit in Fig. 3. and 
have seven circuits in one bundle : hence if. the 
lamps are the same distance from the machine there 
will be the same loss, since there is the same amount 
of copper carrying the current for the seven lamps. 



IN ELECTRICITY. 53 

122. — We have considered to some extent the 
multiple circuit, and now we will compute the wire 
for the mains of an incandescent circuit 1,000 16- 
candle-power lamps, the lamps to be put in one 
large building just 3,000 feet from the dynamo or 
station. This will mean 6,000 feet of wire large 
enough to carry current for 1,000 incandescent 
lamps, each lamp to take y 2 ampere when burning ; 
hence we must arrange to lead away 500 amperes 
of current. 

123. — Since the distance is quite great for this 
kind of a circuit we will decide on eight volts drop, 
hence our machine will have to work at 118 volts 
pressure. On consulting a wiring table we will 
find that we will have to use the No. 0000 wire, B 
& S. gauge, for 50 lamps at. this distance. No, 
0000 wire has a resistance of .051 ohms to the thous- 
and feet. This multiplied by six, since we have 
got to have 6,000 feet of circuit, gives us .306 ohms ; 
.306 ohms multiplied by 25 amperes — the current 
that 50 lamps will take — equals 7.65, or very 
nearly the eight volts. 

124. — We learned farther back that ohms multi- 
plied by amperes gave the voltage necessary to 
make the amperes of current flow through the 
ohms resistance. 

We have demonstrated that it will take a 0000 
wire for 50 of our lamps; hence for 1,000 it will 
take 1,000 divided by 50 equals 20, or twenty 0000 
wires. There are 2 1 1,600 circular mils in one No. 



54 SHARPSTEEN S I 1 SS< >NS 

oooo wire ; hence for twenty of them we will get a 
circular millage of 20 times 211,600 or 4,232,000 
circular mils. 

125. — Xo. 0000 wire weighs 639.33 pounds to the 
thousand feet, and since our circuit is 6,000 feet 
out to the building to be lighted and back, we will 
have to multiply this by six, which gives us 3835.98 
pounds for one of our 0000 circuits, and since we 
must have twenty of these, we multiply again by 
20 and get 76.719.60 pounds or about 38 tons, of 
2,000 pounds, of wire for a circuit of onlv 1.000 
lamps. 

126. — We see at once that this will not do, as 
the copper will cost too much, and we commence 
to look up some other method. 

127. — If we were using water and the cost of our 
energy was small we might use larger dynamos 
and put the pressure up to 140 volts, and waste 30 
volts times 500 amperes or 13,000 watts of energy 
in the circuit when the lights are all on. This 
would reduce the size of our copper to a Xo. 3 wire 
B. & S. gauge for 30 lamps, and still Ave would 
have to use 159 pounds of Xo. 3 to the thousand 
feet x 6 x 20 which is 19,080 pounds, or about 9^ 
tons of bare copper. 

128. — After having discovered how essential it 
was to put incandescent lamps on a multiple cir- 
cuit pure and simple, the next problem that pre- 
sented itself was decreasing the amount of copper 
for the circuits. One of the first things that sug- 



IX ELECTRICITY. 



35 



gested itself was to make the resistance of the in- 
candescent lamps as high as possible. All the 
early incandescent lamps were run in series, hence 
the filament was large and had to carry the whole 
current of the machine or the series of batteries, 
as they were very often worked from batteries. 

129. — It was soon found that the highest prac- 
tical voltage was 1 10 or 120 volts. This makes the 
resistance of the 120- volt lamp, when burning, 240 
ohms if it takes y 2 ampere at 120 volts. This 
seems like a very high resistance for a strip of 
carbon so short as that in an incandescent lamp. 

130. — To illustrate what a difference it would 
make in the amount of copper used, we will con- 
sider that we were going to use 220 instead of 1 10- 
volt lamps. The current would then be reduced 
to 250 amperes, just one-half of what it was be- 
fore, and the E. M. F. , or voltage, would be doubled, 
hence we would want 220 volts for lamps, plus 
eight volts for loss, or 228 volts. 

131. — If we divide our lamps into 20 groups for 
convenience, as we did at first, we find that each 
group will take a No. o wire with a drop of 7.38 
volts with the fifty lamps, or \2y 2 amperes to the 
group. Twenty Xo. o wires 6,000 feet long gives 
us about nineteen tons of copper, which is just 
one-half of what was used with the eight volts 
loss. By raising the voltage from no to 220 we 
could save over nineteen tons of bare copper on 
1,000 lamps 3,000 feet from station; this is moving 



56 SH IRPSTEEN'S I ESS< >NS 

in the right direction, it is plain to be seen. It is 
supposed that the 220-volt lamps would take only 
' 4 ampere each. 

132. — As stated previous to this, on reaching 
1 10 volts this was about the limit of voltage for 16- 
candle-power lamps, and the reduction of copper 
had to be looked for in some other direction. The 
next step was the three-wire system, which is a 
good device patented in this country by T. A. Edison. 



CHAPTER XVI. 

THREE -WIRE SYSTEM. 

133. — The study of the three-wire system is good 
to widen one's conception of the transmission of 
large currents. 

134. — To work to advantage there should be at 
least two machines . 

135. — We will consider that we have a town to 
light which will take a load of 1,000 lamps during 
the evening when the station has the most load to 
carry. We will compute the size of the feeders 
and connect them to the mains. To do this work 
it will take two 250-ampere machines of about 125 
volts each. We will consider that the center of distri- 
bution is 3,000 feet from the station. We will ar- 
range the machines and circuits as in Fig. 8 . 

1 36. — E and F are the two machines, A, B, C and D 
are the brushes on the commutators 

137. — We will assume now that the machines 
have each a pressure of 1 10 volts at the brushes. 
We will put a heavy wire across from brush B to 
brush C, attach our wire O to brush A. and our 
wire R to brush D. 

138. — Xow the machines are connected in series 
or their pressures are added together : hence we 



SHARPSTEEN S LESS< >NS 




□0 



^0 VOLTS 



-O 



IN ELECTRICITY. $9 

have between Q and R, 220 volts. One of the first 
questions that comes up is, "How are you going 
to work 1 10-volt lamps on a 220-volt circuit?" Well, 
it can be done very easily. We will put a lamp 
across from S to K, but of what use is that, since K 
is a dead wire? Well, we will put another lamp 
from K to T, then we have the circuit closed and 
two lamps in series across a 220-volt circuit, and 
since they are no- volt lamps it will take just 220 
volts to make them burn properly. 

139. — The remark would come from some person 
at once : "Why, that seems like a very cumber- 
some device, and of what use is it ? " It seems to 
sweep away the simplicity of the multiple system, 
but such is not the case ; it dispenses with some of 
the very bad features of the multiple system, as it 
is used with two wires. 

140. — In planning the wiring for our 1,000 lights 
3,000 feet from the station we found that we must 
reduce the amount of copper somehow. We found 
what a great saving could be made in copper if we 
could use 220-volt lamps; well, some will see at a 
glance that this three-wire plan has done what we 
could not do by raising the voltage of the lamps, 
and still we can use the 1 10-volt lamps. 

141. — We have only to carry out y 2 ampere for 
two Jamps, when as with the two-wire plan we 
would have to transmit out ]/ 2 ampere for each 
lamp. 

142. — There is one quite serious drawback, and 



6o 



SHARPSTEEN S LESSONS 



that is this: If lamp No. i is turned out, lamp 
Xo. 2 will also go out; that same old trouble that 
comes up in the series system. This is all very 
nicely arranged for and demonstrated in Fig-. Xo. 9. 




— O 



4- 



o 



IN ELECTRICITY. 6 I 

There is a small third wire run out from H, or 
the wire connecting the two machines together, 
hence the term three-wire system, and this third 
wire connects with the circuit P. Now there are 
two independent circuits, and if there are ten or 
twelve lamps put on between wires M and P, and 
none between P and N, machine No. i carries 
them ; and if there should be lamps turned on be- 
tween P and N, and none on the other side, then 
machine No. 2 would do all the work. 

143. — Some persons will see at once that we still 
have two circuits and no apparent saving in copper ; 
but the third wire can be quite small, compared 
with the outside wires, as this third wire has only 
to carry the difference of loads between the two 
sides, and the wiring can be so carefully done that 
the load of lamps will go on both sides almost 
alike, hence there will be no current to speak of in 
the third wire. 

144. — In practice the third wire is put in almost 
as heavy as either of the other two, then if anything 
should happen to one of the main wires the third 
wire would carry half the load with the other main. 

145. — There is another good reason why the third 
wire should be almost equal in carrying capacity to 
the outside wires, and that is this : During the 
hours when the load is light, the whole system of 
wiring in a town or small-sized city can be con- 
nected up as a simple two- wire system, and the 
whole load carried by one small machine, and thus 



62 



SHARPSTEEN S LESSONS 



save the wear and tear on a part of the machinery 
and reduce the consumption of coal. 

146. — By referring to Fig. 10 it will be seen that 




machine No. 2 is cut out from its circuit and a wire 
A B put across from Q to R, which makes one 
main out of Q and R and another out of P, or the 



IN ELECTRICITY 



63 



third wire. Under these conditions if the third 
wire, or P, is of proper size one machine can carry 
quite a load before the loss through Pgets excessive. 
147. — In small stations where this is put in prac- 
tice there is a change-over switch used, which en- 




^1 



o 



CD 



ables a person to make the change very quickly, so 

as not to leave the lamps out for any length of time. 

148. — Thus far we have been trying to get some 

knowledge of the fundamental principles of the 



64 sharpsteen's less 

low-pressure multiple systems of wiring. N 

ill try and give this knowledge a little 
ercise. and add to it a little strength. 

149. — We have not computed the feeders for our 
3,000 lamps, and this we will try and attend to now. 

150. — In Fig. 11 we have our two machines of 
250 anipe: t - sach, and will run three wires. A. B and 
C. that we will call feeders. These connect the 
machines with the mains D E. F G, and H I 
connected to main D E, B to main F G, C to main 
H I. 

1 5 1 . — We want to compute the sizes of mains for 
a drop of not less than three volts from the point 
where the feeder comes into the main, to the point 
where the last lamps are taken off out near the end. 
bis drop of three volts is to take place when the 
whole load of 250 amperes is passing through the 
feeders and mains. 

::. — The feeders, which are 3,000 feet long 
from the machine to the mains, we will estimate 
copper for, so as to have a loss of 16 volts. 

: — The center of distribution is where the 
feeders connect with the mains. In this case at 
the point on the mains directly out from the station, 
if the center of the load was going to be on one 
side or the other of this point, the feeders would 
need to run up or down the street to that center. 

154. — The question as to why 16 volts drop in 
the feeders and only 3 in the mains will sug- 
gest itself to some persons. The reason is this : 



IN ELECTRICITY. 65 

We are to tap on lamps all along the mains, and 
never want more than three volts difference in the 
feeders between any two points where lamps are 
tapped on. We don't care to tap lamps on the 
mains, as we want to make the drop in them ex- 
cessive when the load is on, so as to save the ex- 
pense of putting in so large copper. 

155. — From our former figures we know that we 
want about a No. 3 wire, B. & S. gauge, if we di- 
vide the circuit into twenty parts, as we did before. 
No. 3 wire has a resistance of .205 ohms to the 
1,000 feet, and this multiplied by six, since it takes 
six thousand feet out and back, will give us .1230 
ohms for one of our circuits ; and a twentieth of 
our current now is 250 divided by 20, or 12^ ; 
1.23 ohms multiplied by 12^ amperes current 
would give us 15.37, or a little less than 16 volts 
drop. 

1,000 feet of No. 3 wire, B. & S. gauge, weighs 
159.03 pounds, hence 6,000 feet will weigh 954,18, 
and this multiplied by 20, the number of wires 
run, will give us 1908.60, or a little over 9.5 tons. 

156. — We don't mean that it would be advisable 
to run twenty No. 3 wires, this would hardly be 
practicable, but this is a good method to use in 
computing wire sizes where we have a case sim- 
ilar to this we are studying, since it keeps our 
quantities small and makes them easy to handle ; 
and when we get a wire selected for a part of the 
load we can multiply by the number of divisions and 



66 sharpsteen's lessons 

get the size wire necessary to do the work alone. 
If the wire be very large, when the manufacturer 
gets the order he will arrange the strands so as to 
get the proper number of circular mils. 

157. — Suppose that we found that we wanted a 
wire to carry a certain amount of current with a 
certain drop or loss. With a circular milage of 23, 
1 16 or very near this size, the manufacturer would, 
on referring to tables that he might have, find that 
he could use five Xo. 14 wires B. & S. gauge 
to make up the wire ordered. These he would 
bundle together and put on the insulation. If no 
insulation was wanted they could be put in wire- 
rope shape and used just the same. 

158. — For so small a wire as 23, 1 16 circular mils, if 
the wire was not ordered stranded, the manufact- 
urer might ship in one solid wire, but for very large 
wires similar to what we have been computing, they 
would have to be stranded or they could not be 
handled very well. 

159. — To get back to our circuit of twenty No. 3 
wires B. & S. gauge, one Xo. 3wirehasinit 52,634 
circular mils, and 20 would have twenty times 
this amount, or 1,052,680 circular mils, which would 
make a wire about as large as most of the mills 
could turn out with insulation upon it. This would 
be quite easily strung in a subway, but would want 
a good stiff pole line to hold it properly, and would 
necessitate having a good man to superintend put- 
ting it up. 



IN ELECTRICITY 



67 



!6o. — In Fig. No. 12 we have a plan of a three- 
wire system similar to the way that it might be in- 
stalled in some town where the load was not too far 



So 




01 






5 



a 






I* 



o 
r 




from the station. We will consider that the distance 
from the station or machines Nos. 1 and 2 to the 



68 sharpsteen's lessons 

mains H, I and J is 3,000 feet. The machines we 
will consider are each 250 ampere and 120 volt. 

161. — We will also consider that we are to wire 
up just one half of the load with motors and lamps, 
but put in the feeders and mains large enough for 
the whole load. 

We will allow for 16 volts drop in our feeders 
with the full load. Dividing our 250 amperes by 
5 will give us 50 amperes, which is more convenient 
to work with ; 1,000 feet of No. 0000 wire has a 
resistance of .051 ohms, and this multiplied by 6, 
since there are 3,000 feet of wire out and 3,000 feet 
back, will give us .306 ohms, and this multiplied 
by our 50 amperes gives us 15.3 or the number of 
volts necessary to force the 50 amperes of current 
through the 6,000 feet of Xo. 0000 wire, which is 
very nearly the 16 volts loss that we concluded to 
allow. 

162. — Then we are to understand that the two 
outside wires of our feeders must be equivalent in 
size to five 0000 wires, and we will put in copper 
equivalent to two 0000 wires for our third wire. 

163. — In our feeders we now have arranged for 
twelve 0000 wires 3,000 feet long, or 36,000 feet of 
0000 wire which has a weight of 639.33 pounds 
to the thousand feet. This means 23,015 pounds 
or 1 1. $ tons of 2,000 pounds each. The feeders A, 
B and C unite with the mains at H, I and J. The 
little loop indicates where the wires cross each other. 



CHAPTER XVII. 

MAINS, FEEDERS AND SERVICE WIRES. 

164. — Our mains H, I and J we will consider are 
1,000 feet long from one extreme to the other, or 
500 feet each side of the point near I, or where the 
two third wires meet. We wiil put the load only 
on one end of the mains, and consider that the other 
end is to be a very near duplicate. 

165. — Now there are many things here to be ob- 
served. Right at the point where the feeders meet 
the mains, we take off a set of auxiliary mains to 
to run up another street, and on these auxiliary 
mains we have wired up 160 plus 120 lamps, equals 
280 lamps, 70 amperes plus \]/ 2 amperes for a one- 
half-horse-power motor, which would make 74.% 
amperes that the first set of mains will not have to 
carry; 74^ taken from 125 — the one-half load we 
were going to wire for — will give us S Ql A amperes 
to carry out in the direction of the load that we 
have been putting on. 

166. — The first tap is 300 feet, and here there is 
a five-horse-power motor tapped off on one side, tak- 
ing about 20 amperes with full load, and a set 
of auxiliary mains on the other side of the street 
taking off 60 lamps or 15 amperes. This will 



/O SHARPSTEEN S LESSONS 

make 20 plus 15 amperes, or 35 amperes, plus 15 
amperes or 50 amperes that have got to be carried 
to this point. You may ask, "Why speak of the 
1 5 amperes here for the lamps on the end of the 
circuit" but you must recollect that the mains have 
got to carry it even if it be not tapped off until we 
get farther along the street. 

167. — Then we have 50 amperes that have got to 
be carried 300 feet with not more than three volts 
loss, since three volts loss in the mains is what we 
are to confine ourselves to. 

168. — No, this is not right, since we have got to 
compute our copper for a drop of only three volts 
for our 60 lamps on the end of the line, and that is 
200 feet farther. Now we have a puzzler, but it is 
quite a simple thing if we go at it right. 

169. — For the present we will drop the 60 lamps 
on the end of the circuit and compute our copper 
for the 35 amperes to be carried 300 feet. 

170. — A No. 1 wire has a resistance of .129 ohms 
to the thousand feet, and we want to use 300 feet 
twice, or 600 feet. 

171. — 600 feet is .6 of a thousand; so we mul- 
tiply .6 by .129 and get .774, and this multiplied 
by our 35 amperes gives us 2.7 volts; this is very 
nearly the right size of bare copper. 

172. — Now we have 15 amperes to be carried for 
500 feet from the feeders; this means 1,000 feet of 
wire to carry 1 5 amperes with a loss of 3 volts. 

173. — A No. 3 wire, B & S gauge, has a resist- 



IN ELECTRICITY. J\ 

ance of .205 ohms to the thousand feet, and this 
.205 ohms multiplied by our 15 amperes gives us 
three volts, hence No. 3 wire is what we want. 

174. — This would necessitate running two cir- 
cuits, or four wires, along 300 feet of our line and 
would take 151.72 pounds No. 1, and 159 pounds 
No. 3 B. & S. gauge, in all 310.72. For so short a 
distance it might be better to run only one wire, 
which would necessitate using more copper. 

175. — By putting in only one circuit we would 
have to carry the whole 50 amperes in one wire for 
300 feet, and by using No. 00 wire we would get a 
loss of 2.43 volts, or very nearly 2^ volts, and 
then we would have to run as large as a No. 00 wire 
the balance of the 200 feet, since we have only y 2 
volt left to keep with our 3 volts loss . By using a 
No. 00 wire for the balance of the way we would 
lose .48 volts for the 15 amperes. 

176. — Running No. 00 wire the whole distance 
would necessitate the use of 1,000 feet of it, which 
would weigh about 402 pounds without any insu- 
lation, as compared to 310.72 pounds with the two 
circuits. For a longer distance the two circuits 
would be better if we held close to the three volts 
loss. 

177. — Examples: 

[a] If the auxiliary mains and service wires are 
to have a drop of two volts with all the lamps on, 
and it is 100 feet from the mains to the service 
wires running to the 20 lamps and 60 feet from this 



72 siiarpsteen's lessons 

point to where the service for the 40 lamps tap off, 
and the service wires in both cases are 20 feet long, 
or in other words it is 20 feet from the auxiliary 
mains to the branch or main blocks just inside the 
building, what size copper will have to be used in 
the auxiliary mains, from the mains out to the 
tap for the 20 lamps, and from the tap for the 20 
lamps to the tap for the 40 lamps, and what size 
bare copper in each set of service wires ? 

[£] If on the ends of the mains at E, F and G we 
have to run the service wires 100 feet long to reach 
the 60 lamps, what size bare copper will it be neces- 
sary to put up so as to have one volt loss with the 
whole number of lamps on ? 

\c] With all the lamps on and taking the amount 
of current estimated that they were to take, and 
the motors running, each taking their full load es- 
timate of current, will there be any current in the 
third wire passing back to station, and if any, how 
much? 

178. — Some persons may not see clearly why the 
five-horse-power motor is connected onto the two 
outside wires. One good reason is because the five- 
horse-power motor can be built for 220-volt cur- 
rent very easily. Another reason is, if the motor 
was tapped on between the main and the third 
wire, that it would throw the load out of balance, 
and make quite a large current flow through the 
third wire. 

179. — If it is better to put the five-horse-power 



IN ELECTRICITY. 73 

motor from main to main, why put the ^-horse- 
power motor from main to third wire ? One rea- 
son is that a ^-horse-power is cheaper to build for 
1 10 volts than for 220, and another reason that it 
will handle easier on a no than on a 2 20- volt cir. 
cuit. 

180.— At the points III, IV, V and VI on the 
mains and third wire are small wires attached, and 
at the other end of these wires are pressure indi- 
cators I and II, placed at a convenient place in the 
station, so that the person in charge can see what 
the pressure is at the mains. This arrangement is 
used in many places, and these small wires run- 
ning back are called pressure wires. 

181. — With our three- wire system the pressure 
at the machines would vary between the outside 
wires, or the feeders, from 220 volts with a very 
small load, to 232 volts with a full load, and be- 
tween the same feeders and the third wire the pres- 
sure would vary from 110 volts, with no load, to 
116 volts, with a full load. 



CHAPTER XVIII. 



ALTERNATING CURRENTS. 



182. — Some of us may think that so much space 
devoted to the low-pressure three-wire system is 
hardly right, when almost all the town and city 
lighting is done with a higher pressure, and with 
an alternating current . 

183. — Right here we might say that the circuits 
of a thousand-volt alternating current are all ar- 
ranged on the multiple system, but since the pres- 
sure is so much higher, the wiring is simpler since 
much lighter wire can be used. 

184. — By way of illustration as to how much less 
copper is used in practice with the alternating cur- 
rent, we will compute the size of wire that is neces- 
sary to carry current at 1,030 volts pressure, up to 
the point where our feeders meet the mains in 
Fig. Xo. 10. 

185. — Instead of 16 volts loss as adopted in our 
three-wire system, we will use up 30 volts, and con- 
sider that we are going to use 100- volt lamps in 
place of 1 10-volt as used in the other system. 

186. — With the 1,030 volts we will consider that 
we are to use one machine and two wires. 

187. — Some one will say at once that "30 volts 
loss is terrible. We demonstrated this before ; it 



IN ELECTRICITY. 75 

takes so much energy to force the current through 
the wire." At first thought this seems true, but 
on reflection one finds this is not the case. 

188. — With the 1 10-volt circuit we lost 30 volts 
out of 1 10. You see that 30 taken from 110 re- 
duces it very much, but 30 taken from 1,000 don't 
make much impression upon it . 

189. — If we used 100- volt lamps in our two- wire 
system, and computed our mains for three volts loss, 
it would be the same as a thousand- volt circuit 
with 30 volts loss. 

190. — The 1 00- volt circuit we would have to make 
103 at the machine, and the 1,000 -volt circuit 1,030. 
It is plain that 1.030 divided by 10 would give us 
103, or we can make ten 103 -volt circuits out of 
1,030 volts. Now we can plainly see what advan- 
tage the high pressure is; we have 30 volts to 
lose in the circuit, and it don't mean very much 
energy. Some very bright fellow will conclude at 
once that we are wrong, since 30 volts loss is just 
so much loss, be it in a 1,030-volt circuit or in a 
1 40- volt circuit. Such would be the case if the 
quantities of current were the same, but they are 
not, which we will now demonstrate. 

191. — A good no-volt 16-candle-power lamp 
would possibly take a little more than y 2 ampere 
in most cases, but for convenience we will consider 
that our 16-candle-power 100-A'olt lamps are going 
to take y 2 ampere each. This will make 500 am- 
peres of current that will be used at the point 



/6 MIARPSTEEX's LESIONS 

where our transformers are used to transform the 
current down from 1030 to 103 volts. 

1 92. --The primary current, or main current, of 
1030 volts will have only one-tenth the amperage, 
since the pressure is ten times as high. One-tenth 
of 500 would give us 50, hence we have only to 
use 50 amperes in the high pressure wires to carry 
energy for 1,000 16-candle-power lamps. Fifty 
amperes multiplied by 30 volts gives us 1,500 watts 
or about two-horse power, which, you see, is very 
small compared to our 30 volts loss with the two- 
wire system. 

193. — We will try a No. o wire for our mains. 
No. o wire has a resistance of . 102 ohms to the 
thousand feet, and 6,000 feet would have . 102 ohms 
multiplied by 6, or .612 ohms, and this multiplied 
by 50 amperes would give us 30.600, or just a lit- 
tle more than 30 volts. 

194. — It is plain that No. o wire is large enough. 
6,000 feet of which will weigh 1.854 pounds with- 
out any insulation . With the three-wire system 
it takes over eleven tons with a very heavy drop to 
do the same work. The saving in copper is plain 
to be seen. 



Gauge, Diameter, Weight, Length and Resistance of 
Pure Copper Wire. 



American 

or 

Brown & Sharpe 

Gauge. 


u 

CD 

+a 

CD 

I 

s 


Area. 


Weight, 

Sp. Gr.— 8.889. 


Length. 


Resistance of Pure 
Copper at 75° Fahrenheit, 




CO 




3 "S 

•S o 


CD :P 




CD +3 


CD 


Ohms 


No. 




19 

o 


c8 fi, 


CO § 
& S 
1-3 IH 


+3 2 

CD o 

CD &. 


as 

o pH 


CD o 
CD U 


Per Pound. 


0000.... 


460.000 


211600.00 


4475.33 


639.33 


1.56 


.051 


19605.69 


. 0000798 


000.... 


409.640 


167805.00 


3549.07 


507.01 


1.97 


.064 


15547.87 


.000127 


00.... 


364.800 


133079.40 


2814.62 


402.09 


2.49 


.081 


12330.36 


.000202 


0.... 


324.950 


105592.50 


2233.28 


319.04 


3.13 


.102 


9783.63 


.000320 


1... 


289.300 


83694.20 


1770.14 


252.88 


3.95 


.129 


7754.66 


. 00051 


2. .. 


257.630 


66373.00 


1403.79 


200.54 


4.99 


.163 


6149.78 


.000811 


3.... 


229.420 


52634.00 


1113.20 


159.03 


6.29 


.205 


4876.73 


. 001289 


4.... 


204.310 


41742.00 


882.85 


126.12 


7.93 


.259 


3867 . 62 


. 00205 


5.... 


181 . 940 


33102.00 


700.10 


100.01 


10.00 


.326 


3067.06 


.00326 


6 


162.020 


26250.50 


555.20 


79.32 


12.61 


.411 


2432.22 


.00518 


7.... 


144.280 


20816.00 


440.27 


62.90 


15.90 


.519 


1928.75 


.00824 


8... 


138.490 


16509.00 


349.18 


49.88 


20.05 


.654 


1529.69 


.01311 


9.... 


114.430 


13094.00 


276.94 


39.56 


25.28 


.824 


1213.22 


.02083 


10... 


101.890 


10381 . 00 


219.57 


31.37 


31.88 


1.040 


961.91 


. 03314 


11.... 


90.742 


8234.00 


174.15 


24.88 


40.20 


1.311 


762.93 


. 05269 


12 ... 


80.808 


6529.90 


133.11 


19.73 


50.69 


1.653 


605.03 


.08377 


13.... 


71.961 


5178.40 


109.52 


15.65 


63.91 


2.084 


476.80 


.13321 


14... 


64.084 


4106.80 


86.86 


12.41 


80.59 


2.628 


380.51 


.2118 


15. .. 


57.068 


3256.70 


68.88 


9.84 


101.63 


3.314 


301.75 


.3368 


16.... 


50.820 


2582.90 


54.63 


7.81 


128.14 


4.179 


239.32 


.5355 


17.... 


45.257 


2048.20 


43.32 


6.19 


161.59 


5.269 


189.78 


.8515 


18.... 


40.303 


1624.30 


34.35 


4.91 


203.76 


6.645 


150.50 


1.3539 


19.... 


35.390 


1252.40 


26.49 


3.78 


264.26 


8.617 


116.05 


2.2772 


20. . . . 


31.961 


1021.50 


21.61 


3.09 


324.00 


10.566 


94.65 


3.423 


21... 


28.462 


810.10 


17.13 


2.45 


408.56 


13.323 


75.06 


5.443 


22.... 


25.347 


642.70 


13.59 


1.94 


515.15 


16.799 


59.53 


8.654 


23. . . . 


22.571 


509.45 


10.77 


1.54 


649.66 


21.185 


47.20 


13.763 


24 ... 


20.100 


404.01 


8.54 


1.22 


819.21 


26.713 


37.43 


21.885 


25.... 


17.900 


320.40 


6.78 


.97 


1032.96 


33.684 


29.69 


34.795 


26.... 


15.940 


254.01 


5.37 


.77 


1302.61 


42.477 


23.54 


55.331 


27.... 


14.195 


201.50 


4.26 


.61 


1642.55 


53.563 


18.68 


87.979 


28... 


12.641 


159.79 


3.38 


.48 


2071.22 


67.542 


14.81 


139.893 


29.... 


11.257 


126.72 


2.68 


.38 


2611.82 


85.170 


11.74 


222.449 


30.... 


10.025 


100.50 


2.13 


.30 


3293.97 


107.391 


9.31 


353.742 


31.... 


8.928 


79.71 


1.69 


.24 


4152.22 


135.402 


7.39 


562.221 


32.... 


7.950 


63.20 


1.34 


.19 


5236.66 


170.765 


5.86 


894.232 


33.... 


7.080 


50.13 


1.06 


.15 


6602.71 


215.312 


4.64 


1321.646 


34. . . . 


6.304 


39.74 


.84 


.12 


8328.30 


271.583 


3.68 


2261.82 


35.... 


5.614 


31 . 52 


.67 


.10 


10501.35 


642.443 


2.92 


3596.104 


36.... 


5.000 


25.000 


.53 


.08 


13238.83 


431.712 


2.32 


5715.36 


37.... 


4.453 


19.83 


.42 


.06 


16691.66 


544.287 


1.84 


9084.71 


38.... 


3.965 


15.72 


.34 


.05 


20854.65 


686.511 


1.46 


14320.26 


39.... 


3.531 


12.41 


.27 


.04 


26302.23 


865.046 


1.16 


22752.6 


40.... 


3.144 


9.89 


.21 


.03 


33175.94 


1091.865 


.92 


36223.59 



